v4.19.13 snapshot.
diff --git a/arch/arm/mm/cache-v4wt.S b/arch/arm/mm/cache-v4wt.S
new file mode 100644
index 0000000..a0982ce
--- /dev/null
+++ b/arch/arm/mm/cache-v4wt.S
@@ -0,0 +1,206 @@
+/*
+ * linux/arch/arm/mm/cache-v4wt.S
+ *
+ * Copyright (C) 1997-2002 Russell king
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * ARMv4 write through cache operations support.
+ *
+ * We assume that the write buffer is not enabled.
+ */
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/assembler.h>
+#include <asm/page.h>
+#include "proc-macros.S"
+
+/*
+ * The size of one data cache line.
+ */
+#define CACHE_DLINESIZE 32
+
+/*
+ * The number of data cache segments.
+ */
+#define CACHE_DSEGMENTS 8
+
+/*
+ * The number of lines in a cache segment.
+ */
+#define CACHE_DENTRIES 64
+
+/*
+ * This is the size at which it becomes more efficient to
+ * clean the whole cache, rather than using the individual
+ * cache line maintenance instructions.
+ *
+ * *** This needs benchmarking
+ */
+#define CACHE_DLIMIT 16384
+
+/*
+ * flush_icache_all()
+ *
+ * Unconditionally clean and invalidate the entire icache.
+ */
+ENTRY(v4wt_flush_icache_all)
+ mov r0, #0
+ mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
+ ret lr
+ENDPROC(v4wt_flush_icache_all)
+
+/*
+ * flush_user_cache_all()
+ *
+ * Invalidate all cache entries in a particular address
+ * space.
+ */
+ENTRY(v4wt_flush_user_cache_all)
+ /* FALLTHROUGH */
+/*
+ * flush_kern_cache_all()
+ *
+ * Clean and invalidate the entire cache.
+ */
+ENTRY(v4wt_flush_kern_cache_all)
+ mov r2, #VM_EXEC
+ mov ip, #0
+__flush_whole_cache:
+ tst r2, #VM_EXEC
+ mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
+ mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache
+ ret lr
+
+/*
+ * flush_user_cache_range(start, end, flags)
+ *
+ * Clean and invalidate a range of cache entries in the specified
+ * address space.
+ *
+ * - start - start address (inclusive, page aligned)
+ * - end - end address (exclusive, page aligned)
+ * - flags - vma_area_struct flags describing address space
+ */
+ENTRY(v4wt_flush_user_cache_range)
+ sub r3, r1, r0 @ calculate total size
+ cmp r3, #CACHE_DLIMIT
+ bhs __flush_whole_cache
+
+1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
+ tst r2, #VM_EXEC
+ mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ ret lr
+
+/*
+ * coherent_kern_range(start, end)
+ *
+ * Ensure coherency between the Icache and the Dcache in the
+ * region described by start. If you have non-snooping
+ * Harvard caches, you need to implement this function.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+ENTRY(v4wt_coherent_kern_range)
+ /* FALLTRHOUGH */
+
+/*
+ * coherent_user_range(start, end)
+ *
+ * Ensure coherency between the Icache and the Dcache in the
+ * region described by start. If you have non-snooping
+ * Harvard caches, you need to implement this function.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+ENTRY(v4wt_coherent_user_range)
+ bic r0, r0, #CACHE_DLINESIZE - 1
+1: mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ mov r0, #0
+ ret lr
+
+/*
+ * flush_kern_dcache_area(void *addr, size_t size)
+ *
+ * Ensure no D cache aliasing occurs, either with itself or
+ * the I cache
+ *
+ * - addr - kernel address
+ * - size - region size
+ */
+ENTRY(v4wt_flush_kern_dcache_area)
+ mov r2, #0
+ mcr p15, 0, r2, c7, c5, 0 @ invalidate I cache
+ add r1, r0, r1
+ /* fallthrough */
+
+/*
+ * dma_inv_range(start, end)
+ *
+ * Invalidate (discard) the specified virtual address range.
+ * May not write back any entries. If 'start' or 'end'
+ * are not cache line aligned, those lines must be written
+ * back.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+v4wt_dma_inv_range:
+ bic r0, r0, #CACHE_DLINESIZE - 1
+1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ ret lr
+
+/*
+ * dma_flush_range(start, end)
+ *
+ * Clean and invalidate the specified virtual address range.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+ .globl v4wt_dma_flush_range
+ .equ v4wt_dma_flush_range, v4wt_dma_inv_range
+
+/*
+ * dma_unmap_area(start, size, dir)
+ * - start - kernel virtual start address
+ * - size - size of region
+ * - dir - DMA direction
+ */
+ENTRY(v4wt_dma_unmap_area)
+ add r1, r1, r0
+ teq r2, #DMA_TO_DEVICE
+ bne v4wt_dma_inv_range
+ /* FALLTHROUGH */
+
+/*
+ * dma_map_area(start, size, dir)
+ * - start - kernel virtual start address
+ * - size - size of region
+ * - dir - DMA direction
+ */
+ENTRY(v4wt_dma_map_area)
+ ret lr
+ENDPROC(v4wt_dma_unmap_area)
+ENDPROC(v4wt_dma_map_area)
+
+ .globl v4wt_flush_kern_cache_louis
+ .equ v4wt_flush_kern_cache_louis, v4wt_flush_kern_cache_all
+
+ __INITDATA
+
+ @ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
+ define_cache_functions v4wt